ABSTRACT Comparative Bullet Lead Analysis (CBLA) was discredited as a forensic discipline largely due to the absence of cross-discipline input, primarily metallurgical and statistical, during development and forensic/judicial application of the practice. Of particular significance to the eventual demise of CBLA practice was ignorance of the role of statistics in assessing probative value of claimed bullet “matches” at both the production and retail distribution levels, leading to overstated testimonial claims by expert witnesses. Bitemark comparisons have come under substantial criticism in the last few years, both due to exonerations based on DNA evidence and to research efforts questioning the claimed uniqueness of bitemarks. The fields of fire and arson investigation and of firearm and toolmark comparison are similar to CBLA and bitemarks in the absence of effective statistical support for these practices. The features of the first two disciplines are examined in systemic detail to enhance understanding as to why they became discredited forensic practices, and to identify aspects of the second two disciplines that pose significant concern to critics.

中文翻译：

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缺乏统计和科学精神：法医实践缺乏共同点

摘要比较法子弹头分析（CBLA）被誉为法医学科，这主要是由于在该实践的开发和法证/司法应用过程中缺乏跨学科的输入，主要是冶金和统计方面的输入。对于最终取消CBLA惯例特别重要的是，忽略了统计数据在生产和零售分销层面评估所要求的子弹“匹配”的证明价值中的作用，导致专家证人夸大了证明要求。在过去的几年中，由于基于DNA证据的夸大其词以及对声称的咬痕的独特性提出质疑的研究工作，Bitemark的比较受到了广泛的批评。在缺乏有效的统计支持的情况下，火灾和纵火调查以及枪支和工具标记比较领域与CBLA和咬痕类似。对前两个学科的特征进行了系统的详细检查，以增强对为什么它们成为不良的法医实践的理解，并确定后两个学科中引起评论家极大关注的方面。